Ambient light control

Abstract

The invention relates to a control device ( 10 ) for use in an ambient light control system ( 20 ) for controlling ambient light entering a space ( 1 ) through an opening ( 2 ). An ambient light prediction unit ( 11 ) provides ambient light prediction values, which are predictions of an ambient light property at the opening ( 2 ). An ambient light adjusting unit ( 12 ) provides, at different ambient light adjusting time points, an ambient light adjusting signal depending on the ambient light prediction values for an upcoming ambient light prediction time period. The ambient light adjusting signal is adapted for use by an ambient light modifying element ( 22 ) for modifying the entering of ambient light into the space ( 1 ) through the opening ( 2 ). By taking the predicted ambient light conditions at the opening ( 2 ) into account, necessary adjustments can be made at temporally spaced ambient light adjusting time points, resulting in fewer disturbances of the users.

The invention claimed is: 
     
       1. A control device for use in an ambient light control system for controlling ambient light entering a space through an opening, the control device comprising:
 an ambient light prediction unit for providing ambient light prediction values, wherein an ambient light prediction value is a prediction of an ambient light property at the opening, and 
 an ambient light adjusting unit for providing, at different ambient light adjusting time points, an ambient light adjusting signal depending on the ambient light prediction values for an upcoming ambient light prediction time period, wherein the ambient light adjusting unit is adapted to provide the ambient light adjusting signal at several ambient light adjusting time points, wherein the ambient light adjusting signal is adapted for use by an ambient light modifying element for modifying the entering of ambient light into the space through the opening wherein the ambient light adjusting signal at a first ambient light adjusting time point is provided depending on the ambient light prediction values for the upcoming ambient light prediction time period, wherein the upcoming ambient light prediction time period is the time period from the first ambient light adjusting time point until a second ambient light adjusting time point, wherein the first ambient light adjusting time point comprises a first ambient light prediction value, and wherein the first ambient light prediction value for the first ambient light adjusting time point comprises the following probability:
     P ( v>β,t ) 
 
 
       where P is a probability that an ambient light property at the opening exceeds an ambient light property threshold value at a given time of day, t is the given time of day, v is the ambient light property at the opening, and β is the ambient light property threshold value. 
     
     
       2. The control device according to  claim 1 , wherein the ambient light property at the opening is a vertical illuminance of the ambient light at the opening. 
     
     
       3. The control device according to  claim 1 , wherein the ambient light adjusting unit is adapted to provide the ambient light adjusting signal depending on a comparison of the ambient light prediction values for the upcoming ambient light prediction time period with at least one ambient light prediction threshold value. 
     
     
       4. The control device according to  claim 3 , wherein the ambient light adjusting unit is adapted to provide the ambient light adjusting signal such that when the ambient light prediction values for the upcoming ambient light prediction time period are not all either larger than a first ambient light prediction threshold value or smaller than a second ambient light prediction threshold value, the second ambient light prediction threshold value being smaller than the first ambient light prediction threshold value, the ambient light adjusting signal indicates that no modification shall be made to the entering of ambient light into the space through the opening. 
     
     
       5. The control device according to  claim 4 , wherein a past ambient light sensing time period comprises one or more past days, wherein the ambient light prediction unit is adapted to provide the ambient light prediction value for a given time of day such that it is indicative of a probability that the ambient light property at the opening exceeds an ambient light property threshold value at the given time of day. 
     
     
       6. The control device according to  claim 4 , wherein a past ambient light sensing time period comprises one or more past days, wherein the ambient light prediction unit is adapted to provide the ambient light prediction value for a given time of day depending on a received sensed ambient light values for the given time of day at the one or more past days. 
     
     
       7. The control device according to  claim 1 , wherein the control device further comprises a sensed ambient light receiving unit for receiving sensed ambient light values indicative of the ambient light property at the opening , wherein the ambient light prediction unit is adapted to provide the ambient light prediction values depending on the received sensed ambient light values for a past ambient light sensing time period. 
     
     
       8. The control device according to  claim 1 , wherein the ambient light adjusting unit is adapted to provide the ambient light adjusting signal such that it indicates that the amount of ambient light entering the space through the opening shall be reduced, if a currently received sensed ambient light value exceeds a sensed ambient light threshold value. 
     
     
       9. The control device according to  claim 1 , wherein the control device comprises a predicted weather data receiving unit for receiving predicted weather data, wherein the ambient light adjusting unit is adapted to provide the ambient light adjusting signal depending on the received predicted weather data. 
     
     
       10. The control device according to  claim 1 , wherein the control device comprises a sensed occupancy state receiving unit for receiving a sensed occupancy state indicative of the space being occupied, wherein the ambient light adjusting unit is adapted to provide the ambient light for modifying the entering of ambient light into the space through the opening when the received sensed occupancy state indicates that the space is not occupied. 
     
     
       11. The control device according to  claim 1 , wherein the ambient light adjusting signal is adapted to indicate to the ambient light modifying element that an amount of ambient light entering a space through an opening shall be reduced, if:
     P ( v>β,t )>δ 1  for  t   1   ≦t≦t   2  
 
 
       where δ 1  is a first ambient light prediction threshold value, and t 1 , t 2  define the upcoming ambient light prediction time period. 
     
     
       12. The control device according to  claim 11 , wherein the ambient light adjusting signal is adapted to indicate to the ambient light modifying element that an amount of ambient light entering a space through an opening shall be increased, if:
     P ( v>β,t )<δ 2  for  t   1   ≦t≦t   2  
 
 
       where δ 2  is a second ambient light prediction threshold value, wherein β 2  is smaller than the first ambient light prediction threshold value δ 1 . 
     
     
       13. A control method for use in an ambient light control method for controlling ambient light entering a space through an opening, the control method comprising:
 providing ambient light prediction values, by an ambient light prediction unit, wherein an ambient light prediction value is a prediction of an ambient light property at the opening, and 
 providing, at different ambient light adjusting time points comprising at least a first ambient light adjusting time point and a second ambient light adjusting time point, an ambient light adjusting signal depending on the ambient light prediction values for an upcoming ambient light prediction time period, by an ambient light adjusting unit, wherein the ambient light adjusting signal is adapted for use by an ambient light modifying element for modifying the entering of ambient light into the space through the opening, wherein the upcoming ambient light prediction time period is the time period from the first ambient light adjusting time point until the second ambient light adjusting time point, wherein the first ambient light adjusting time point comprises a first ambient light prediction value, and wherein the first ambient light prediction value for the first ambient light adjusting time point comprises the following probability:
     P ( v>β, t ) 
 
 
       where P is a probability that an ambient light property at the opening exceeds an ambient light property threshold value at a given time of day, t is the given time of day, v is the ambient light property at the opening, and β is the ambient light property threshold value. 
     
     
       14. The control method according to  claim 13 , wherein the ambient light adjusting signal is adapted to indicate to the ambient light modifying element that an amount of ambient light entering a space through an opening shall be reduced, if:
     P ( v>β,t )>δ 1  for  t   1   ≦t ≦t   2  
 
 
       where δ 1  is a first ambient light prediction threshold value, and t 1 , t 2  define the upcoming ambient light prediction time period. 
     
     
       15. The control method according to  claim 14 , wherein the ambient light adjusting signal is adapted to indicate to the ambient light modifying element that an amount of ambient light entering a space through an opening shall be increased, if:
     P ( v>β,t )<δ 2  for  t   1   ≦t ≦t   2  
 
 
       where δ 2  is a second ambient light prediction threshold value, wherein δ 2  is smaller than the first ambient light prediction threshold value δ 1 .